Yes, have the Leveling -> Bfa -> Drustvar guide. Also tried in Legion with the Legion -> Leveling -> Class campaign. Flew from Dalaran to Thunder Totem.
I did additional experiments switched to horde mage with horde leveling guide selected did flight, had no problem. then selected alliance warlock boated from same place to place as I did with the first alliance mage Boralus to Anglepoint. no problems. The only variable I see are the realms. Whisperwind.
addition just did a little run around with a lvl 1 on Whisperwind alliance same realm and faction. I am baffled why I am having trouble on what looks like just this one character. Never put time in playing the others beside doing a travel. gonna delete all info I have from troubled Character i have throughout my warcraft folder to see if fresh info there helps